SYNTHESES, STRUCTURES, AND REACTIONS OF THE FIRST ROTATIONAL ISOMERS OF STABLE SELENOBENZALDEHYDES, RIS[BIS(TRIMETHYLSILYL)METHYL]SELENOBENZALDEHYDES, AND THEIR ETA(1)-TUNGSTEN COMPLEXES

Deselenation of a cyclic polyselenide mixture, Tbt(s)CHSe(n) 5, result ed in the formation of Tbt(s)CHSe 3a, which gave its head-to-tail dime r 12 upon concentration of the reaction solution although it was stabl e in a dilute solution. Thermolysis of 12 gave an equilibrium mixture of 12, 3a, and its rotational isomer Tbt(a)CHSe 3b, and 3b was isolate d as a solid stable even in air. Reaction of 3a and 3b with W(CO)(5) . THF gave the corresponding eta(1)-selenoaldehyde tungsten complexes 4 a and 4b, respectively. Some reactions of 4a were carried out to give products accompanied by decomplexation. (C) 1997 Elsevier Science Ltd.